Electric furnace



O. A. COLBY ELECTRIC FURNACE Filed Dec. 2, 1922 April 14, 1925.-

INVENTOR I]. Colby.

A'i'TORNEY 0m BY WITNESSES:

Patented Apr. 14, 1925.

ORA A. COLBY, OF IRWIN. PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC 8?.

MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC FURNACE.

7 '0 all whom it may concern:

Be it known that I, ORA A. COLBY, a citizen of the United States, and a resident of Irwin, in the county'of West-moreland'and State of Pennsylvania, have invented a new and useful Improvement in Electric Fur-' naces, ofiwhich the following is a specification.

My invention relates to electric furnaces and particularly to electric resistance fur naces. v

The object of my invention isto provide a heating element of relatively simple. rugged. and inexpensive construction for an electric resistance furnace.

In practicing my invention,, I provide a plurality of refractory walls enclosing. a furnace chamber, the inner surface of certain of said walls having a plurality of spaced depressions therein. Refractory cleats located in the depressions have a laterally grooved, flat surface projectingfrom the wall, and'flat refractory plates operatively engaging the projecting surface of the cleats constituting a mutile for the furnace chamber. A' resistor member comprising a relatively heavy rod or bar extends through the grooves in the cleats and therebetween to be supported thereby.

In the single sheet of drawings.

Figure 1 is a view, in vertical lateral section, of an electric resistance furnace em-.

' bodying my invention,

i Fig. 2 is a view, in front elevation, of one of the walls thereof,

Fig.3 1s a view, in vertical section, of the walls shown in Fig. 2, taken on the line IIL-III thereof,

Fig. 4 is a view, in vertical longitudinal section, of a refractory cleat, and

Fig. 5 is a view, in front elevation, of a resistor member located in the refractory cleats.

A furnace structure 11 comprises an outer metallic casing 12 having a plurality of supporting members 13 suitably secured thereto. An outer lining 14 comprises a plurality of bricks or blocks of a suitable refractory heat-insulating material. 15 comprises a plurality of bricks or blocks of a suitable refractory high-temperatureresisting material, the bricks or blocks com- An inner lining Application filed December 2 1922. Serial No. 604,508.

pressions 17. The depth of the members '18 is such that a.

portion thereof projects into the furnace chamber 16, which portion is provided with a plurality of laterally extending, open grooves 19.

resistor member 21, comprising a plurality of substantially parallel-extending, straight-convolutions of a preformed relatively heavy rod or bar of a suitable resistor material, such as nichrome, has portions of the individual convolutions located in the grooves 19 and extends therebetween and therebeyond substantially as illustrated in Fig. 5 of. the drawing. The distance between the spaced depressions 17 and therefore the distance between the supporting cleats 19, maybe made in accordance with the area of cross-section of the resistor member 21, which-must be such as to permit of the resistor member being substantially selfsustaining between the spaced supporting cleats. v

A plurality of flat plates 22, of a suitable refractory high-temperature-resisting material is located inthe furnace chamber 16 adjacent to and operatively engaging the outer grooved surfacesof the supporting cleats 18. Any suitable or desired means for 17 or it may be shorter, and may be employed holding the muffle plates 22 in their proper operative positions in the furnace chamber may be employed, and I have illustrated the plates as being provided with interlocking edges, although any other desired method may be employed. I I

When it is necessary to replace one of the resistor members 21, the muflle plates 22 are removed from the furnace, after which the damaged resistor 21 or one of the cleats 18, may be removed, and'be replaced by new parts after which the mufile plates are again moved into their proper operative positions in the furnace longitudinally thereof.

I have not illustrated a terminal construction or terminal members for the resistor 21, as any suitable or desired construction may be employed.

Various modifications and changes in detail and arrangement may be made without departing from the spirit and scope of the invention, and such modifications are intended to becovered by the appended claims.

I claim as my lIIVQIltIOIII 1. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber and having a plurality of spaced recesses therein, cleats in said recesses having a. surface extending into said chamber provided with a plurality of laterally extending grooves therein and a resistor member extending through said grooves and between said cleats.

2. In an electric furnace, in combination, a plurality of refractory walls enclosing a furnace chamber and having a plurality of spaced recesses therein, cleats in said recesses having a surface extending into said chamber provided with a plurality of laterally extending grooves therein, a resistor member extending through said grooves and between said cleats, and a muffle plate in said chamber operatively en aging the outer grooved surface of said c eats.

3. In an electric furnace, in combination, a refractory wall constituting a part of an enclosure for a furnace chamber and having a plurality of spaced recesses therein, refractory cleats fitting into said recesses and having a portion extending into said chamber provided with aplurality of laterally extending spaced grooves therein and a resistor member supported by said cleats adjacent said furnace wall.

4. In an electric furnace, in combination, a refractory wall constituting a part of an enclosure for a furnace chamber and having a plurality of spaced recesses therein, refractory cleats fitting into said recesses and having a portion extending into said chamber provided with a plurality of laterally ex tending spaced grooves therein and a resistor member comprising a relatively heavy and preformed rod of a refractory resistor material extending through the grooves in said cleats and being substantially self-supporting therebetween.

5. In an electric furnace, in combination, a refractory Wall constituting a. part of an enclosure for a furnace chamber and having a plurality of spaced recesses therein, refractory members fitting into said recesses and supported by said wall and a relatively heavy and preformed resistor member extending through and between said refractory members and supported thereby adjacent the inner surface of said refractory Wall.

6. In an electric furnace, in combination, a refractory wall constituting a part of an enclosure for a furnace chamber and having a plurality of spaced recesses therein, refractory members fitting into said recesses and supported by said wall, a relatively heavy and preformed resistor member extending through and between said refractory members and supported thereby adjacent the inner surface of said refractory wall and a relatively thin flat refractory mullle plate operatively engaging the inner surfaces of said refractory member.

7. In an electric furnace, in combination, a refractory wall constituting a part of an enclosure for a furnace chamber and having a plurality of spaced recesses therein, rcfractory resistor-supporting members fitting into said recesses and supported by said wall. and having a grooved surface extending beyond the inner surface of said refractory wall, and a relatively heavy and preformed resistor member extending through the grooves in said resistor-supporting members and therebetween and thercbeyond closely adjacent to the inner surface of the refractory wall.

In testimony whereof, I have hereunto subscribed my name this 27th day of November, 1922.

ORA A. COLBY. 

